PAVLOVIAN CONDITIONING ALTERS CORTICAL MICROTUBULE-ASSOCIATED PROTEIN-2

THREE experiments indicate that Pavlovian conditioning to tone alters microtubule-associated protein-2 (MAP-2) in the temporal cortex. First , increased MAP-2 immunohistochemistry was evident in temporal cortex following tone-shock pairings but not light-shock pairings. In the sec ond experiment, animals given tone paired with shock (compared with an imals trained with tone unpaired with shock or given tone only) showed MAP-2 immunohistochemical changes in the temporal cortex, as well as in the frontal and cingulate cortex, the hippocampus and amygdala. In experiment 3, quantitative immunoblots showed decreased intact MAP-2 a nd increased breakdown products selectively in temporal cortex followi ng fear conditioning to tone. Conditioning to tone also increased size s of MAP-2 rich pyramidal somata and apical dendrites in temporal and frontal cortex.